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Title: Interface properties and built-in potential profile of a LaCr O 3 / SrTi O 3 superlattice determined by standing-wave excited photoemission spectroscopy

Abstract

LaCrO 3(LCO)/SrTiO 3(STO) heterojunctions are intriguing due to a polar discontinuity along [001], exhibiting two distinct and controllable charged interface structures [(LaO) +/(TiO 2) 0 and (SrO) 0/(CrO 2) -] with induced polarization, and a resulting depth-dependent potential. In this study, we have used soft- and hard-x-ray standing-wave excited photoemission spectroscopy (SW-XPS) to quantitatively determine the elemental depth profile, interface properties, and depth distribution of the polarization-induced built-in potentials. We observe an alternating charged interface configuration: a positively charged (LaO) +/(TiO 2) 0 intermediate layer at the LCO top/STO bottom interface and a negatively charged (SrO) 0/(CrO 2) - intermediate layer at the STO top/LCO bottom interface. Using core-level SW data, we have determined the depth distribution of species, including through the interfaces, and these results are in excellent agreement with scanning transmission electron microscopy and electron energy-loss spectroscopy mapping of local structure and composition. SW-XPS also enabled deconvolution of the LCO and STO contributions to the valence-band (VB) spectra. Using a two-step analytical approach involving first SW-induced core-level binding-energy shifts and then VB modeling, the variation in potential across the complete superlattice is determined in detail. As a result, this potential is in excellent agreement with density functional theorymore » models, confirming this method as a generally useful tool for interface studies.« less

Authors:
 [1];  [1];  [2];  [3];  [3];  [4];  [3];  [5];  [5];  [5];  [6];  [6];  [7];  [6];  [8];  [6];  [1]
  1. Univ. of California, Davis, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
  2. Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Auburn Univ., Auburn, AL (United States)
  3. Synchrotron SOLEIL, Gif-sur-Yvette (France)
  4. Peter Grünberg Institut PGI-6, Julich (Germany); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
  5. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
  6. Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
  7. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Peter Grünberg Institut PGI-6, Julich (Germany)
  8. Peter Grünberg Institut PGI-6, Julich (Germany)
Publication Date:
Research Org.:
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES)
OSTI Identifier:
1563966
Alternate Identifier(s):
OSTI ID: 1478562
Grant/Contract Number:  
AC02-05CH11231; SC0014697; 10122
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Physical Review B
Additional Journal Information:
Journal Volume: 98; Journal Issue: 16; Journal ID: ISSN 2469-9950
Publisher:
American Physical Society (APS)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY

Citation Formats

Lin, S. -C., Kuo, C. -T., Comes, R. B., Rault, J. E., Rueff, J. -P., Nemšák, S., Taleb, A., Kortright, J. B., Meyer-Ilse, J., Gullikson, E., Sushko, P. V., Spurgeon, S. R., Gehlmann, M., Bowden, M. E., Plucinski, L., Chambers, S. A., and Fadley, C. S. Interface properties and built-in potential profile of a LaCrO3/SrTiO3 superlattice determined by standing-wave excited photoemission spectroscopy. United States: N. p., 2018. Web. doi:10.1103/physrevb.98.165124.
Lin, S. -C., Kuo, C. -T., Comes, R. B., Rault, J. E., Rueff, J. -P., Nemšák, S., Taleb, A., Kortright, J. B., Meyer-Ilse, J., Gullikson, E., Sushko, P. V., Spurgeon, S. R., Gehlmann, M., Bowden, M. E., Plucinski, L., Chambers, S. A., & Fadley, C. S. Interface properties and built-in potential profile of a LaCrO3/SrTiO3 superlattice determined by standing-wave excited photoemission spectroscopy. United States. https://doi.org/10.1103/physrevb.98.165124
Lin, S. -C., Kuo, C. -T., Comes, R. B., Rault, J. E., Rueff, J. -P., Nemšák, S., Taleb, A., Kortright, J. B., Meyer-Ilse, J., Gullikson, E., Sushko, P. V., Spurgeon, S. R., Gehlmann, M., Bowden, M. E., Plucinski, L., Chambers, S. A., and Fadley, C. S. Mon . "Interface properties and built-in potential profile of a LaCrO3/SrTiO3 superlattice determined by standing-wave excited photoemission spectroscopy". United States. https://doi.org/10.1103/physrevb.98.165124. https://www.osti.gov/servlets/purl/1563966.
@article{osti_1563966,
title = {Interface properties and built-in potential profile of a LaCrO3/SrTiO3 superlattice determined by standing-wave excited photoemission spectroscopy},
author = {Lin, S. -C. and Kuo, C. -T. and Comes, R. B. and Rault, J. E. and Rueff, J. -P. and Nemšák, S. and Taleb, A. and Kortright, J. B. and Meyer-Ilse, J. and Gullikson, E. and Sushko, P. V. and Spurgeon, S. R. and Gehlmann, M. and Bowden, M. E. and Plucinski, L. and Chambers, S. A. and Fadley, C. S.},
abstractNote = {LaCrO3(LCO)/SrTiO3(STO) heterojunctions are intriguing due to a polar discontinuity along [001], exhibiting two distinct and controllable charged interface structures [(LaO)+/(TiO2)0 and (SrO)0/(CrO2)-] with induced polarization, and a resulting depth-dependent potential. In this study, we have used soft- and hard-x-ray standing-wave excited photoemission spectroscopy (SW-XPS) to quantitatively determine the elemental depth profile, interface properties, and depth distribution of the polarization-induced built-in potentials. We observe an alternating charged interface configuration: a positively charged (LaO)+/(TiO2)0 intermediate layer at the LCOtop/STObottom interface and a negatively charged (SrO)0/(CrO2)- intermediate layer at the STOtop/LCObottom interface. Using core-level SW data, we have determined the depth distribution of species, including through the interfaces, and these results are in excellent agreement with scanning transmission electron microscopy and electron energy-loss spectroscopy mapping of local structure and composition. SW-XPS also enabled deconvolution of the LCO and STO contributions to the valence-band (VB) spectra. Using a two-step analytical approach involving first SW-induced core-level binding-energy shifts and then VB modeling, the variation in potential across the complete superlattice is determined in detail. As a result, this potential is in excellent agreement with density functional theory models, confirming this method as a generally useful tool for interface studies.},
doi = {10.1103/physrevb.98.165124},
url = {https://www.osti.gov/biblio/1563966}, journal = {Physical Review B},
issn = {2469-9950},
number = 16,
volume = 98,
place = {United States},
year = {2018},
month = {10}
}

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Figures / Tables:

FIG. 1 FIG. 1: (a) Schematic of the superlattice made up of 10 bilayers of LCO and STO, consisting of 5 unit cells of LCO, 17.6 Å thick, and 10 unit cells of STO, 39.2 Å thick, grown epitaxially on a Nb-doped STO(001) substrate. The two sources of standing-wave structure in themore » rocking curves are indicated: Bragg reflection from the multilayer with period $$d$$ $ML$ and Kiessig fringes associated with the full thickness of the multilayer stack $$D$$ $ML$. (b) The x-ray absorption coefficient over the La $$M$$ 5 edge. (c) The real (delta) and imaginary (beta) parts of the index of refraction, as derived by Kramers-Kronig analysis. To enhance the reflectivity and thus the strength of the standing wave effect, two photon energies were chosen, below and above the La $$M$$ 5 absorption maximum. The electric field strength distribution derived from x-ray optics calculations at these two energies, (d) 829.7 eV and (e) 831.5 eV as a function of sample depth and incidence angle. Note the significant shift in position between the two energies. The corresponding calculated photoemission yields with depth, (f) and (g), plotted on log10 scales.« less

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Works referenced in this record:

Impact of built-in potential across LaFeO3/SrTiO3 heterojunctions on photocatalytic activity
journal, May 2016


Interface Structure, Band Alignment, and Built-In Potentials at LaFeO 3 / n SrTiO 3 Heterojunctions
journal, November 2016


Interface-Induced Polarization in SrTiO 3 -LaCrO 3 Superlattices
journal, February 2016


Atomic subshell photoionization cross sections and asymmetry parameters: 1 ⩽ Z ⩽ 103
journal, January 1985


Projector augmented-wave method
journal, December 1994


Observation of polar vortices in oxide superlattices
journal, January 2016


Direct Measurement of Valence-Charge Asymmetry by X-Ray Standing Waves
journal, January 2000


Band-Gap Reduction and Dopant Interaction in Epitaxial La,Cr Co-doped SrTiO 3 Thin Films
journal, December 2014


Two-Dimensional Electron Gases at Complex Oxide Interfaces
journal, July 2014


Theoretical study of Schottky-barrier formation at epitaxial rare-earth-metal/semiconductor interfaces
journal, April 2010


Efficient iterative schemes for ab initio total-energy calculations using a plane-wave basis set
journal, October 1996


Concentration and chemical-state profiles at heterogeneous interfaces with sub-nm accuracy from standing-wave ambient-pressure photoemission
journal, November 2014


Electron-energy-loss spectra and the structural stability of nickel oxide: An LSDA+U study
journal, January 1998


X-ray standing-wave investigations of valence electronic structure
journal, September 2001


Charge transfer and interfacial magnetism in (LaNiO 3 ) n /(LaMnO 3 ) 2 superlattices
journal, October 2013


Restoring the Density-Gradient Expansion for Exchange in Solids and Surfaces
journal, April 2008


Dynamic interface rearrangement in LaFeO 3 / n SrTiO 3 heterojunctions
journal, November 2017


Some future perspectives in soft- and hard- X-ray photoemission
journal, August 2014


Band Alignment, Built-In Potential, and the Absence of Conductivity at the LaCrO 3 / SrTiO 3 ( 001 ) Heterojunction
journal, November 2011


Probing the Origin of Interfacial Carriers in SrTiO 3 –LaCrO 3 Superlattices
journal, January 2017


Surface-interface coupling in an oxide heterostructure: Impact of adsorbates on LaAlO 3 / SrTiO 3
journal, November 2015


Resonant photoemission of La and Yb at the 3d absorption edge
journal, February 2003


Suppression of Near-Fermi Level Electronic States at the Interface in a LaNiO 3 / SrTiO 3 Superlattice
journal, September 2011


Multiband Optical Absorption Controlled by Lattice Strain in Thin-Film LaCrO 3
journal, February 2013


Ultralow Contact Resistance at an Epitaxial Metal/Oxide Heterojunction Through Interstitial Site Doping
journal, May 2013


Atomically engineered ferroic layers yield a room-temperature magnetoelectric multiferroic
journal, September 2016


Band alignment of epitaxial SrTiO3 thin films with (LaAlO3)0.3-(Sr2AlTaO6)0.7 (001)
journal, September 2015


Origin of the light green color and electronic ground state of La Cr O 3
journal, February 2008


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